• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.89-93
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• 2009

Amorphous $Ge_{1-x}Mn_x$ semiconductor thin films grown by low temperature vapor deposition were annealed, and their electrical and magnetic properties have been studied. The amorphous thin films were $1,000{\sim}5,000\;{\AA}$ thick. Amorphous $Ge_{1-x}Mn_x$ thin films were annealed at $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$ and $700^{\circ}C$ for 3 minutes in high vacuum chamber. X-ray diffraction analysis reveals that as-grown $Ge_{1-x}Mn_x$ semiconductor thin films are amorphous and are crystallized by annealing. Crystallization temperature of amorphous $Ge_{1-x}Mn_x$ semiconductor thin films varies with Mn concentration. Amorphous $Ge_{1-x}Mn_x$ thin films have p-type carriers and the carrier type is not changed during annealing, but the electrical resistivity increases with annealing temperature. Magnetization characteristics show that the as-grown amorphous $Ge_{1-x}Mn_x$ thin films are ferromagnetic and the Curie temperatures are around 130 K. Curie temperature and saturation magnetization of annealed $Ge_{1-x}Mn_x$ thin films increase with annealing temperature. Magnetization behavior and X-ray analysis implies that formation of ferromagnetic $Ge_3Mn_5$ phase causes the change of magnetic and electrical properties of annealed $Ge_{1-x}Mn_x$ thin films.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.97-97
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• 1993

Primary tumor arises infrequently in the parotid gland and generally, only about 20 to 40 percent of which prove to be malignant. They are characterized by histopathologic diversity, slow tumor growth, significant proportion of patients who have received previous treatment elsewhere. We have reviewed retrospectively 101 cases of parotid gland tumors which were treated for the recent eight years (1985-1992), Non-neoplastic tumor-like lesions were all excluded.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.15-23
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• 2005

Mucin glycoproteins are the primary carriers of the oligosaccharide moieties that constitute the blood group substances in human saliva. The aim of this study was to determine whether or not the conversion of either the A or B blood group antigens to the H antigen can occur during the degradation process of stored saliva samples. Forty subjects (20 subjects in each A and B blood group) identified as secretors were enrolled in this study. Fresh whole saliva samples and their clarified supernatants were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by SDS-PAGE and immunoblotting. Among the subjects showing the conversion in whole saliva, glandular saliva samples were obtained from 8 subjects (4 subjects in each A and B blood group). Submandibular-sublingual saliva (SMSL) and a mixture of SMSL and parotid saliva (PS) were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by the same method. The obtained results were as follows: 1. In the clarified samples of whole saliva, the A antigen was detected as being either intact (5%) or degraded molecules (95%) after the 1 week period. Conversion of the A antigen to the H antigen was detected in 5 subjects (25%). In the unclarified samples, the A antigen was either detected as degraded molecules (90%) or was not detected (10%). Conversion of the antigen had occurred in 4 subjects (20%). 2. In the clarified samples of whole saliva, the B antigen was detected as intact (20%) or as degraded molecules (65%) or was not detected (15%) after the 1 week period. Conversion of the B antigen to the H antigen was detected in 7 subjects (35%). In the unclarified samples, the B antigen was detected as intact (5%) or as degraded molecules (65%), or was not detected (30%). Conversion of the antigen was observed in 2 subjects (10%). 3. In the glandular saliva samples, only one of the four subjects displayed an antigenic conversion from the A to H antigen or from the B to H antigen. The conversion had occurred in both the SMSL samples and the SMSL and PS mixture. No degradation of the antigens was detected in the other three samples of the A or B blood groups, nor was there any conversion. The results demonstrated that conversion of the blood group antigens could occur in saliva, and suggested that the enzymes responsible for the conversion are present in saliva. Further studies on the origin and activity of the specific glycosidases in saliva as well as quantitative measurements of the antigenic conversion will be needed.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.2
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• pp.129-153
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• 2017

Fair Competition policy in aviation field has been discussed since open skies policy began in 1970s. This issue has been also the main topic in the ICAO's Worldwide Air Transport Conference, the Air Transport Symposium, etc. ICAO defines competition as the existent or potential rivalry between two or more operators, carriers or groups, striving for advantages in the same market based on different prices, qualities and services. In a broader sense, the definition includes more various meanings; reasonable, fair, effective, and unrestricted competitions. Nowadays, competition laws and regulations to air transportation have been applied more frequently and the issues varies from antitrust immunity, mergers and alliances, abuse of dominant positions, capacity dumping and predatory pricing, sales and marketing, to airport charges and fees, state aid and loan guarantees. Now, the competition among the airlines or nations in aviation industry is changing to cooperation level. A lot of airlines try to survive by various cooperation methods. Therefore the policy of Korean aviation industry should be developed, taking so-called "the viewpoint of national aviation industry ecosystem" into consideration and Korean government should prepare a policy of fair competition to cope with it. First, in the process of open skies policy with neighboring countries such as China, Japan and the Middle East, it is necessary to apply the fair competition act and prepare laws and regulations to implement it. Second, the standards of effective ownership and control of air transportation business should be reviewed. Third, in preparation for aviation agreements and liberalization, the Korean aviation industry needs to study and review competition and cooperation issues through the analysis of strict aviation market structure for airlines and airport operations. Fourth, it is necessary to create a fair air transportation environment for the development of air transportation and competitiveness through preemptive policies such as the approval of mergers, acquisitions, JV and the ripple effects analysis.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.211-216
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• 2010

The luminescence properties of $In_{0.5}Ga_{0.5}As/In_{0.5}Al_{0.5}As$ multiple quantum wells (MQWs) grown on $In_{0.5}Al_{0.5}As$ buffer layers have been studied by using photoluminescence (PL) and time-resolved PL measurements. A$1-{\mu}m$ thick $In_{0.5}Al_{0.5}As$ buffer layers were deposited on a 500 nm thick GaAs layer, followed by the deposition of the InGaAs/InAlAs MQWs. In order to investigate the effects of InAlAs buffer layer on the optical properties of the MQWs, four different temperature sequences are used for the growth of InAlAs buffer layer. The growth temperature for InAlAs buffer layer was varied from 320^{\circ}C to $580^{\circ}C$. The MQWs consist of three $In_{0.5}Ga_{0.5}$As wells with different well thicknesses (2.5 nm, 4.0 nm, and 6.0 nm thick) and 10 nm thick $In_{0.5}Al_{0.5}$As barriers. The PL spectra from the MQWs with InAlAs layer grown at lower temperature range ($320-580^{\circ}C$) showed strong peaks from 4 nm QW and 6 nm QW. However, for the MQWs with InAlAs buffer grown at higher temperature range ($320-480^{\circ}C$), the PL spectra only showed a strong peak from 6 nm QW. The strongest PL intensity was obtained from the MQWs with InAlAs layer grown at the fixed temperature of $480^{\circ}C$, while the MQWs with buffer layer grown at higher temperature from $530^{\circ}C$ to $580^{\circ}C$ showed the weakest PL intensity. From the emission wavelength dependence of PL decay times, the fast and slow decay times may be related to the recombination of carriers in the 4 nm QW and 6 nm QW, respectively. These results indicated that the growth temperatures of InAlAs layer affect the structural and optical properties of the MQWs.

• The Korean Journal of Air & Space Law and Policy
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• v.21 no.1
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• pp.135-167
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• 2006

Air service agreements between EU Member States and third countries concluded by Sweden, Finland, Belgium, Luxembourg, Austria, the Netherlands, Denmark and the United Kingdom after the Second World War infringe EU law. They authorize the third countries to withdraw, suspend or limit the traffic rights of air carriers designated by the signatory States. According to the Court of Justice of the European Communities (CJEC), these agreements infringe EU law in two respects. On the one hand, the presence of nationality clauses infringes the right of European airlines to non-discriminatory market access to routes between all Member States and third countries. On the other hand, only the EU has the authority to sign up to this type of commitment where agreements affect the exercise of EU competence, i.e. involve an area covered by EU legislation. The Court held that since the third countries have the right to refuse a carrier, these agreements therefore constitute an obstacle to the freedom of establishment and freedom to provide services, as the opening of European skies to third countries' companies is not reciprocal for all EU airlines. In the conclusion, in order to reconstruct these public international air law, The new negotiations between EU member states and third countries, especially the US, must be designed to ensure an adequate set of principles, so that Member States, in their bilateral relations with third countries in the area of air service, should consider following three models. The 1st, to develop a new model of public international air law such as a new Bermuda III. The 2nd, to reconstruct new freedoms of the air, for example, the 7th, 8th, and 9th freedoms. The 3rd, to explore new approaching models, such as complex system theory explored in the recent social sciences, to make access world-wide global problems instead of bilateral problems between EU member states and United States. The example will show any lessons to air talks between European Union and ROK.

• Korean Journal of Veterinary Research
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• v.25 no.1
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• pp.7-17
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• 1985

Many investigators have been pursuing various attempts so far to produce hepatitis B surface antigen(HBsAg) vaccines using the techniques such as isolation from plasma of chronic HBsAg carrier, recombinant DNA technique or preparation of synthetic peptides specific for immunogenic determinants. Hepatitis B virus can not grow on any cell lines by the tissue culture technique at the present time. The plasma of chronic HBsAg carrier is expensive and its source is limited. The HBsAg from the recombinant DNA technique gave still very low yield. Another approach, therefore, has been initiated to develop a synthetic hepatitis B virus vaccine. The possible use of several distinct synthetic vaccines in prophylaxis can be facilitated by availability of full synthetic immunogens. Peptides synthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins, although the free synthetic peptide can be immunogenic. To understand basic knowledges on the antigenicity and immunogenicity of a synthetic peptide specific for major immunogenic determinant of HBsAg, a nonapeptide, $H_2N^{139}Cys-Thr-Lys-Pro-Thr-Asp-Gly-^{146}Asn-Aba$ COOH, which corresponds to HBsAg amino acid residues 139 to 147, was synthesized by the Merrifield's solid-phase method with a slight modification. The antigenicity and immunogenicity of this specific synthetic peptide were examined comparing with purified plasma-derived natural HBsAg. The results obtained are as follows; 1. The peptide synthesized showed the identical amino acid composition to the theoretical value. The degree of purification and molecular weight were acertained by methods of high performance liquid chromatography and mass spectrometry. 2. Using m-maleimidobenzoyl-N-hydroxysuccinimide ester as a conjugating agent, the synthetic peptide was conjugated to rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin. Their conjugation yields were 8.3, 9.5, 15.8, 13.5, and 11.2%, respectively. 3. The natural HBsAg was purified from plasma of chronic HBsAg carrier. By the electron microscopic observation of the purified natural HBsAg preparation, no Dane particles were observed and the preparation showed negative DNA polymerase activity. 4. Antigenicity of the synthetic peptide and the plasma-derived natural HBsAg was determined by competition radioimmunoassay using $^{125}I$-natural HBsAg. Their 50% inhibitions appeared as $90{\mu}g/ml$ and $0.12{\mu}g/ml$ for the synthetic peptide and the natural HBsAg, respectively. This indicates that the former was about 750-fold less antigenic than the latter. 5. Immunogenicity of the synthetic peptide was determined by administering the peptide-carrier conjugates into rabbits with and without Freund's complete adjuvant. Regardless the carrier proteins and adjuvant, positive immune responses to the synthetic peptide were observed. The higher antibody titers, however, were shown in the groups administered with Freund's complete adjuvant. 6. Immunizing dose 50% in mice of the various peptide-carrier conjugates was 5.47, 6.00, 65.16, 31.25 and $13.03{\mu}g/dose$ for rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin, respectively, while the natural HBsAg showed $0.65{\mu}g/dose$. 7. It was postulated that homologous proteins prefer to heterologous ones as the carriers.

• The Journal of the Korean Society for Microbiology
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• v.8 no.1
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• pp.7-11
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• 1973

The authors identified eighty-eight Shigella cultures among about four thousands specimens collected from all over the country in 1972. Of eighty-eight cultures, seventy-seven cultures belonged to Shigella flexneri and eleven cultures to Shigella sonnei. None of cultures belonging to either subgroup A or C was detected in 1972. Of seventy-seven cultures of Shigella flexneri one was $B_{1b}$, fifty-six were $B_{2a}$, nine were $B_{3a}$, six were $B_{4a}$, three were By and one was each of $B_{3b}$ and $B_{3c}$. Of eleven cultures of Shigella sonnei seven cultures appeared to be phase I and the others phase II. Although there was quite a difference found in the incidence of isolating Shigella organisms between different areas as shown in Table 1, it would not be possible to understand that there might not have been the cases or carriers of Shigella in the areas where the organisms were not isolated in 1972. Concerning the biochemical properties it was not possible to compare the results obtained from the decarboxylase and dihydrolase tests with them obtained in previous years except that of lysine decarboxylase tests since they were not reported individually by the different serotypes in the previous reports. These results obtained in 1972 would be the data for the future comparison. In regards to the antibiotics-sensitivity of Shigella cultures the most of them showed sensitive results to nitrofurantoin, ampicillin, cephalosporin, gentamycin and geopen, and the majority of them appeared to be resistant to cloxacillin, tetracycline and streptomycin by means of the In Vitro tests.

• Journal of Legislation Research
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• no.41
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• pp.401-434
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• 2011

The discussion on the adoption of the horizontal regulatory framework is underway to overcome the problems regarding the vertical regulatory framework resulting from a convergence of broadcasting and telecommunications services. Recently, however, the horizontal regulatory framework shows its limitation to regulate the ecosystem established mainly by Google and Apple. The existing horizontal regulatory framework does not fully reflect the characteristics of the two-sided market and the change in the competition structure in the broadcasting and telecommunications sector. What is important to note is that if the existing horizontal regulatory framework is simply applied to the ecosystem, a regulatory imbalance can be caused among ecosystems. The existing horizontal regulatory framework, which is subject to a value chain structure, categorizes business entities into either contents layer or transmission layer and applies the same regulation to all business entities in the same category. However, in the ecosystem, a keystone-player can be categorized into different layers depending on its strategy. Therefore, if the existing horizontal regulatory framework is applied as it is, the regulatory imbalance between keystone-players located in less regulated areas and keystone-players located in more regulated areas occurs resulting in a distortion of competition. There are two possible ways to establish a new regulatory framework to prevent the distortion of competition likely to be caused by the adoption of a horizontal regulatory system. First, a new ecosystem regulatory framework different from the existing one can be established. Second, the horizontal regulatory framework can be modified to reflect the ecosystem elements. The first approach is hard to adopt given the current situation as the approach requires the analysis of all broadcasting and telecommunications ecosystems including mobile and wired services; currently research and study on the competition conditions in the ecosystems is not enough. Therefore, this paper supports the second approach proposing a modified horizontal regulatory framework through the improvement of institutions and remedies suitable for accommodating the ecosystem elements. This paper intends to propose a way to regulate broadcasting and telecommunications ecosystems taking into consideration the ecosystem elements on top of the Telecommunications Business Act, Broadcasting Act, IPTV Act, the competition condition evaluation system of the Basic Act on Broadcasting and Telecommunications Development, and regulation on common carriers under the Telecommunications Business Act.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.618-626
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• 2019

Stem cell therapy is not expected to bestow any therapeutic benefit because of the low engraftment rates after transplantation.Various cell-carrying scaffolds have been developed in order to overcome this problem. When the scaffold is formed by 3-dimensional (3D) printing, it is possible to create various shapes of scaffolds for specific regions of injury. At the same time, scaffolds provide stem cells as therapeutic-agents and mechanically support an injured region. PCL is not only cost effective, but it is also a widely used material for 3D printing. Therefore, rapid and economical technology development can be achieved when PCL is printed and used as a cell carrier. Yet PCL materials do not perform well as cell carriers, and only a few cells survive on the PCL surface. In this study, we tried to determine the conditions that maximize the cell-loading capacity on the PCL surface to overcome this issue. By applying a plasma treated condition and then collagen coating known to improve the cell loading capacity, it was confirmed that the 3% collagen coating after plasma treatment showed the best cell engraftment capacity during 72 hours after cell loading. By applying the spheroid cell culture method and scaffold structure change, which can affect the cell loading ability, the spheroid cell culture methods vastly improved cell engraftment, and the scaffold structure did not affect the cell engraftment properties. We will conduct further experiments using PCL material as a cell carrier and as based the excellent results of this study.